Calprotectin (synonyms: calgranulin A/B, human leukocyte protein; L1 protein; MRP-8/14; S-100a and b; cystic fibrosis antigen, CFA) is a cellular component of neutrophil granulocytes (defense cells) that is considered a marker of granulocyte migration into the lumen of the intestine as part of an inflammatory process. Lower concentrations of calprotectin are also found in monocytes. Since calprotectin is not degraded during intestinal transit and is very stable in stool, inflammation in the upper intestinal tract can also be detected in stool samples. Calprotectin belongs to the group of fecal inflammatory markers (fecal biomarkers). Fecal calprotectin (FC) makes an important contribution to the diagnosis and follow-up of inflammatory bowel disease (IBD).
The procedure
Material needed
- Stool sample (stability of calprotectin in native stool sample 3-7 days; for longer storage: freeze stool at -20 °C).
Preparation of the patient
- Not known
Disruptive factors
- Very thin or liquid stool (dilution effect).
Normal values (age-dependent)
| Age group | Medians from sub. Studiesµg/g stool (= mg/kg stool) |
| Infants | 150 – 278 |
| Infants up to 4 yrs. | 14 – 49 |
| Adults and children from 4 – 17 yrs. | – 50 |
Calprotectin and diseases (age: adults and children from 4 – 17 yrs).
| Medians from sub. Studies (μg/g stool) (= mg/kg stool). | Rating |
| 10-31 | Healthy (or functional bowel disease such as irritable bowel syndrome). |
| 50-100 | Gray range (control examination in 4-8 weeks) |
| 220 | Diverticulitis |
| 40-420; wide distribution around 150 | Colorectal carcinomas |
| 60-320; frequently > 600 | Crohn’s disease |
| 150-167 | Ulcerative colitis |
Indications
- Suspected inflammatory bowel disease (IBD, e.g., Crohn’s disease, ulcerative colitis).
- Differential diagnosis of functional diseases (eg, irritable bowel syndrome (irritable colon)) and inflammatory diseases.
- Activity markers in inflammatory bowel disease (correlates with the degree of inflammation).
Interpretation
Interpretation of increased values
- Ulcerative colitis – inflammatory bowel disease (IBD).
- Intestinal infections* , unspecified
- Enteropathies (intestinal diseases) caused by non-steroidal anti-inflammatory drugs.
- Diverticulitis – disease of the colon in which inflammation forms in protrusions of the mucosa (diverticula).
- Crohn’s disease – chronic inflammatory bowel disease (IBD); usually runs in relapses and can affect the entire digestive tract; characteristic is the segmental affection of the intestinal mucosa (intestinal mucosa), that is, it may affect several sections of the intestine, which are separated from each other by healthy sections.
- Cystic fibrosis (cystic fibrosis) – genetic disease in which there is production of mucus too viscous, especially in the lungs and gastrointestinal tract.
- Rheumatoid arthritis – inflammatory multisystem disease, usually manifested in the form of synovitis (inflammation of the synovial membrane); correlates with disease activity.
- Medications:
- Non-steroidal anti-inflammatory drugs (NSAIDs; non steroidal anti- inflammatory drugs, NSAID).
- Proton pump inhibitors (PPI).
Interpretation of decreased values
- Not relevant to the disease
Normal calprotectin levels
- Exocrine pancreatic insufficiency – disease of the pancreas associated with insufficient production of digestive enzymes.
- Lactose intolerance (lactose intolerance).
- Food intolerance
- Irritable bowel syndrome
- Celiac disease (gluten intolerance)
Other notes
- In addition to calprotectin, lactoferrin is also considered a marker in inflammatory bowel disease (IBD).
- * To avoid false-positive results, exclusion of an infectious cause is necessary in intestinal disease!
- Serum calprotectin (SC) correlated strongly with fecal calprotectin (FC).
